As is generally well known in the railroad art, the adjacently disposed ends of a pair of railway cars are connected together by various types of coupler arrangements. Such coupling arrangements may use either a conventional type coupler, an articulated type coupler or a drawbar.
A conventional type coupler is an independent unit disposed on an end of each car which interconnect with one another, between adjacent cars, to form a rather easily breakable type connection.
Both the drawbar assemblies and articulated type couplers, on the other hand, are integral type units. These units are adapted to extend between and be secured to the outer end of two adjacent cars to form a substantially semipermanent connection between such cars.
Nevertheless, in either coupling arrangement, a shank end of the coupler member, or the drawbar portion of a slackless drawbar assembly, will extend into the end of a center sill member of a railway car where it is secured so as to transmit the longitudinal forces being exerted to the car body during in-track service.
Prior to the present invention, certain other inventions have been directed to improvements in construction of the center sill member. These construction improvements in the center sill member have been for receiving primarily conventional type coupler members therein. However, these improvements may, also, have application in receiving coupling members of a slackless drawbar type system. By slackless, it is meant that the drawbar (or coupler member) is received within the end of such center sill member in a manner to minimize longitudinal play and/or other movements.
However, it is important for successive railway cars, which are connected together in a train consist, to be able to readily accommodate the relative movement which is encountered between cars when both curves and inclines are being negotiated. In other words, there must be provision made for each car to independently move in each of pitch, yaw and roll modes with respect to the coupler member.
Moreover, there must be some provision made to periodically remove the draft components for repair and/or the replacement of worn or broken parts and, in connection with a slackless drawbar type system, to disconnect connected cars.
Generally, in a slackless drawbar type system, the coupler member is held in such a manner so as to substantially eliminate, or to at least minimize, longitudinal movement with respect to the railway car body. This function may be accomplished, for example, by the provision of a tapered wedge member disposed between the inner surface of a rear wall portion of a pocket casting (secured in the center sill member) and a follower block member which is engageable with a surface located on both the tapered wedge member and the butt end portion of the coupler member.
During normal use, the tapered wedge member will tend to urge the follower block member in a direction away from the end wall portion of the pocket casting and firmly into engagement with the butt end portion of the drawbar member shank. When cars are being pushed, during operation, the longitudinal forces being exerted thereon will cause a compression of the butt end portion of such drawbar member against the follower block member, the tapered wedge member and the end wall portion of the pocket casting.
Conversely, when the railway cars are being pulled, the longitudinal forces being exerted which will tend to separate the drawbar member from the pocket casting are countered in at least some systems, conventional couplers, for example, by a draft key which is a metal bar that normally extends laterally of the car center sill member through aligned slots formed in the sidewall portions of the center sill member and a slot formed in the shank portion of the coupler member and in certain slackless drawbar type systems by a connecting pin member.
In a slackless drawbar system, the drawbar member is normally held tightly between the bearing block member and follower block member by operation of the tapered wedge member which separates the pocket casting and follower block member. Such tapered wedge member tries to compress the follower block member against the butt end portion of the drawbar thereby urging the latter against the bearing block member and the follower block member. In addition, as is known in the railroad art, the mating surfaces disposed on the follower block member and the butt end of such drawbar member are preferably curved to permit the drawbar to pivot slightly in each of a vertical and a lateral direction and to permit the car to roll with respect to the drawbar.
Prior to the present invention, the yoke members which were specifically designed for use only with such slackless drawbar type arrangements have generally been manufactured from a plurality of individual pieces. This makes the installation of the yoke member much more difficult. Furthermore, the use of separate pieces will normally tend to weaken the structure. This is obviously not a desirable condition in a railway application.